5V to 3.3V logic level converter

Question

I am trying to connect an ESP8266 module to an Arduino. Giving the fact that ESP8266 runs at 3.3V and the Arduino at 5V i need a logic level converter from 5V to 3V3.

Is there a way i can build one using discrete components? I searched the web and found recommendations for TXS0104E / 74LVC245 / BSS138, unfortunately none of the local shops sell them.

Although the 3.3V TX pin from the ESP8266 does not require a logic converter since Arduino will read the 3V3 signal as HIGH, i would like to add some protection for the wifi module. Is a 3.3V zenner diode a wise choice for this?

Answer 1

You can use any N-Channel MOSFET, not just BSS138.
It is pretty simple. This is bidirectional level converter:

^{simulate this circuit – Schematic created using CircuitLab}

UPDATE:
By "any" I meant any jellybean small signal mosfet. Simply with low Vgs voltage threshold.

Answer 2

Check if your inputs are 5V tolerant. If not, check if the ESP8266's inputs are diode protected first.

If not, I'd recommend connecting a diode between your 3.3V input and 3.3V supply (A on the input, K on the 3.3V supply).

You should also add a resistor in series with your 5V output to reduce the current when the 5V outputs a logic high.

You need to check however that you input accepts the resulting voltages etc

PS: This does not take many other aspects that you should take into account, like the signal frequencies for example.